Can heterogeneity in ventilation be good?

Selection of the optimal positive end-expiratory pressure (PEEP) to avoid ventilator-induced lung injury in patients under mechanical ventilation is still a matter of debate. Many methods are available, but none is considered the gold standard. In the previous issue of Critical Care, Zhao and colleagues applied a method based on electrical impedance tomography to help select the PEEP that minimized ventilation inhomogeneities. Though promising when alveolar collapse and overdistension are present, this method might be misleading in patients with normal lungs

Os simbolismos dos animais com chifres em bestiários ingleses

Introdução Desde tempos muito remotos que os chifres são encarados pela mentalidade do homem como símbolos. Provavelmente, a associação mais antiga relaciona-os com as fases da lua, justificada pela semelhança entre o formato dos chifres e o do satélite natural. Com o decorrer da História, os chifres se tornaram símbolos mais complexos. Possivelmente decorrente da observação do poder destrutivo destes elementos na natureza, os chifres passaram a estar simbolicamente associados ao poder e à fo..

Os cem olhos do pavão

O pavão é considerado um dos mais bonitos animais da natureza. Essa beleza, no que diz respeito ao imaginário, torna-se elemento-chave nas narrativas e nas artes que associam o pavão com as divindades hindus e budistas, com o orgulho e com a vaidade. Este artigo busca apresentar de que forma os simbolismos do pavão foram transmitidos e adaptados, desde a Índia Antiga até a Europa Medieval, onde a ave figurou na criatividade cristã como emblema da imortalidade de Cristo e dos pregadores da Igreja, acompanhando também narrativas hagiográficas e imagens bíblicas.The peacock is considered one of the most beautiful animals in nature. This beauty, concerning the imaginary, becomes a key element in the narratives and arts that associate the peacock with the Hindu and Buddhist deities, but also with the pride and the vanity. This article tries to show how the symbolism of the peacock was transmitted and adapted from Ancient India to Medieval Europe, where the bird figured in the Christian creativity as an emblem of the immortality of Christ and the preachers of the Church, along with hagiographical narratives and biblical images

Os simbolismos do animais com chifres em bestiários ingleses

Esta tese tem como objetivo identificar e analisar os simbolismos dos animais com chifres no imaginário da Idade Média, focando na produção cultural da Inglaterra a partir dos bestiários, códices que apresentam narrativas polissêmicas, uma vez que abordam características naturais dos animais e que também podem ser acompanhadas por mensagens alegóricas ou edificantes. Os animais com chifres presentes nos manuscritos dos bestiários servem como comprovativo de que tais documentos podem ser interpretados como relevantes suportes da doutrina da Igreja e que os chifres permanecem como símbolos do poder espiritual e secular no período medieval, tal como eram interpretados em tempos pré-cristãos.This thesis aims to identify and analyze the symbolism of horned animals in the imaginery of the Middle Ages, focusing on the cultural production of England from the bestiaries, codices that present polysemic narratives, since they describe natural characteristics of the animals and can also be accompanied by allegorical or enlightenin messages. Horned animals in the bestiaries manuscripts serve as proof that such documents can be interpreted as relevant supporters of Church doctrine and that horns remain as symbols of spiritual and secular power in the medieval period, as interpreted in pre-Christian times

Effects of arterial oxygen tension and cardiac output on venous saturation: a mathematical modeling approach

OBJECTIVES: Hemodynamic support is aimed at providing adequate O2 delivery to the tissues; most interventions target O2 delivery increase. Mixed venous O2 saturation is a frequently used parameter to evaluate the adequacy of O2 delivery. METHODS: We describe a mathematical model to compare the effects of increasing O2 delivery on venous oxygen saturation through increases in the inspired O2 fraction versus increases in cardiac output. The model was created based on the lungs, which were divided into shunted and non-shunted areas, and on seven peripheral compartments, each with normal values of perfusion, optimal oxygen consumption, and critical O2 extraction rate. O2 delivery was increased by changing the inspired fraction of oxygen from 0.21 to 1.0 in steps of 0.1 under conditions of low (2.0 L.min-1) or normal (6.5 L.min-1) cardiac output. The same O2 delivery values were also obtained by maintaining a fixed O2 inspired fraction value of 0.21 while changing cardiac output. RESULTS: Venous oxygen saturation was higher when produced through increases in inspired O2 fraction versus increases in cardiac output, even at the same O2 delivery and consumption values. Specifically, at high inspired O2 fractions, the measured O2 saturation values failed to detect conditions of low oxygen supply. CONCLUSIONS: The mode of O2 delivery optimization, specifically increases in the fraction of inspired oxygen versus increases in cardiac output, can compromise the capability of the "venous O2 saturation" parameter to measure the adequacy of oxygen supply. Consequently, venous saturation at high inspired O2 fractions should be interpreted with caution

CINVEC : Una herramienta multimedial para el análisis vectorial del movimiento

Se presenta el CINVEC, una herramienta multimedia, que facilita la asimilación de los elementos de álgebra vectorial necesarios para comprender y ejercitar contenidos de cinemática correspondientes a la asignatura física de un programa de ingreso de nivel universitario. El alumno reconoce el carácter escalar o vectorial de las distintas magnitudes: posición, desplazamiento, trayectoria, tiempo, velocidad, rapidez, aceleración para finalmente aplicarlas en la descripción de los distintos tipos de movimientos. Se indica los temas incluidos en la herramienta y se presentan ejemplos de aplicación. Este software constituye un medio familiar y ameno para el alumno y le permite profundizar los conocimientos adquiridos en las clases sin limitaciones de tiempo ni espacio.Red de Universidades con Carreras en Informática (RedUNCI

CINVEC : Una herramienta multimedial para el análisis vectorial del movimiento

Se presenta el CINVEC, una herramienta multimedia, que facilita la asimilación de los elementos de álgebra vectorial necesarios para comprender y ejercitar contenidos de cinemática correspondientes a la asignatura física de un programa de ingreso de nivel universitario. El alumno reconoce el carácter escalar o vectorial de las distintas magnitudes: posición, desplazamiento, trayectoria, tiempo, velocidad, rapidez, aceleración para finalmente aplicarlas en la descripción de los distintos tipos de movimientos. Se indica los temas incluidos en la herramienta y se presentan ejemplos de aplicación. Este software constituye un medio familiar y ameno para el alumno y le permite profundizar los conocimientos adquiridos en las clases sin limitaciones de tiempo ni espacio.Red de Universidades con Carreras en Informática (RedUNCI

Fuzzy Modeling of Electrical Impedance Tomography Images of the Lungs

OBJECTIVES: Aiming to improve the anatomical resolution of electrical impedance tomography images, we developed a fuzzy model based on electrical impedance tomography's high temporal resolution and on the functional pulmonary signals of perfusion and ventilation. INTRODUCTION: Electrical impedance tomography images carry information about both ventilation and perfusion. However, these images are difficult to interpret because of insufficient anatomical resolution, such that it becomes almost impossible to distinguish the heart from the lungs. METHODS: Electrical impedance tomography data from an experimental animal model were collected during normal ventilation and apnea while an injection of hypertonic saline was administered. The fuzzy model was elaborated in three parts: a modeling of the heart, the pulmonary ventilation map and the pulmonary perfusion map. Image segmentation was performed using a threshold method, and a ventilation/perfusion map was generated. RESULTS: Electrical impedance tomography images treated by the fuzzy model were compared with the hypertonic saline injection method and computed tomography scan images, presenting good results. The average accuracy index was 0.80 when comparing the fuzzy modeled lung maps and the computed tomography scan lung mask. The average ROC curve area comparing a saline injection image and a fuzzy modeled pulmonary perfusion image was 0.77. DISCUSSION: The innovative aspects of our work are the use of temporal information for the delineation of the heart structure and the use of two pulmonary functions for lung structure delineation. However, robustness of the method should be tested for the imaging of abnormal lung conditions. CONCLUSIONS: These results showed the adequacy of the fuzzy approach in treating the anatomical resolution uncertainties in electrical impedance tomography images

Genetic diversity of Litopenaeus vannamei cultivated in Bahia State, Brazil

O objetivo deste trabalho foi avaliar a variabilidade genética de estoques comerciais do camarão Litopenaeus vannamei, por meio de marcadores RAPD e diferentes métodos estatísticos de análises, em Canavieiras, BA. Vinte primers foram utilizados para a obtenção de 59 marcadores polimórficos. A análise com o programa AMOVA evidenciou diferenciação genética significativa entre os estoques, com ΦST = 0,186 (p < 0,001). Entretanto, as análises obtidas com o programa HICKORY sugeriram não existir estruturação (θβ = 0,002), mas considerável taxa de endogamia dentro dos estoques, em razão, provavelmente, do cruzamento entre indivíduos geneticamente mais similares (f = 0,729). Testes com bootstrap mostraram 48 como o número mínimo de marcadores RAPD adequados para estudos de variabilidade genética nessa espécie. Pelo dendrograma, gerado a partir da matriz de similaridade de Jaccard (Sj), observou-se que nos três estoques comerciais estudados existem animais geneticamente distintos.The objective of this work was to evaluate the genetic variability of commercial stocks of shrimp Litopenaeus vannamei, using RAPD markers and different statistical methods of analysis in Canavieiras, BA, Brazil. Twenty primers were used to obtain 59 polymorphic markers. A significant differentiation among stocks, with ΦST= 0.186 (p < 0.001), was observed by analysis with the software AMOVA. However, an analysis with the software HICKORY suggested no genetic structure (θβ = 0.002), but considerable inbreeding within stocks, possibly due to consanguineous crossings (f = 0.729). Statistical tests with bootstrap indicated 48 as the minimum number of RAPD markers suitable for studies on genetic variability of this species. By the dendrogram produced from the Jaccard similarity matrix, it was observed that the analyzed stocks are composed of genetically different individuals